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Biomedical subjects

D De Silva

Publications and source records attributed to D De Silva.

11 recordsLinked to original sources
PubMed2003

The impact of repeated malaria attacks on the school performance of children.

The impact of repeated malarial infections on the school performance of children was investigated in 571 school children 6-14 years of age in a malaria-endemic area in southern Sri Lanka where both Plasmodium falciparum and P. vivax infections are prevalent. Malaria infections confirmed by microscopy were monitored over a six-year period. School performance was assessed by two specially designed, school grade-specific, test papers for Sinhala language and mathematics. The scores for Sinhala language and mathematics for each school term test for the year 1997 were obtained. Malarial infections were a major predictor of children's performance in language and mathematics after controlling for parent's education, monthly family income, and house type. The education of the father predicted language scores but not mathematics scores. A child who experienced more than five attacks of malaria scored approximately 15% less than a child who experienced less than three attacks of malaria. The data suggest that repeated attacks of malaria have an adverse impact on the school performance of children.

Adult↗
PubMed2002

Structural organization of the estalpha3(1) gene in a Colombian strain of Culex quinquefasciatus differs from that in Cuba.

In Culex mosquitoes (Diptera: Culicidae), the most common mechanism for resistance to organophosphorus (OP) insecticides involves amplification of one or more esterases. Two esterase loci are often involved, with different allelic forms co-amplified. Estalpha3(1) is co-amplified with estbeta1 in a Colombian (COL) strain of Culex quinquefasciatus Say. These two alleles co-migrate on acrylamide gels, often leading to misscoring of the phenotype as elevation of a single estbeta enzyme. By sequencing COL genomic DNA, we determined the estalpha3(1) gene length is 1623 nucleotides. The open reading frame of estalpha3(1) encodes a 540 amino acid protein, as for estalpha2(1) in strain Pel RR from Sri Lanka. The intron/exon boundaries of estalpha3(1) are identical to those of estalpha2(1), suggesting that they are alleles of the same locus. The COL estalpha3(1) gene differs from estaalpha3(2) in strain MRES from Cuba, although they have equivalent electrophoretic mobility, showing that these two strains contain distinct resistance-associated amplicons. Twenty nucleotide differences were scored between the MRES partial 495 bp sequence and that in the COL strain, with two amino acid changes, demonstrating distinct estalpha enzymes. Our sequencing data show 95% identity between the three estalpha genes (each has six introns and seven exons) in OP-resistant Cx. quinquefasciatus. Amplified estalpha3(1) and estbeta1 are at least 10kb apart in temephos-selected COL and 2.7kb apart in Pel RR, whereas these non-amplified genes are only 1.7kb apart in the nonselected parental COL stock, as in Pel SS (susceptible Sri Lankan strain), demonstrating that this region of the genome is susceptible to expansion and contraction.

Amino Acid Sequence↗
PubMed2001

Possible ethnic differences in plasma homocysteine levels associated with coronary artery disease between south Asian and east Asian immigrants.

BACKGROUND: Hyperhomocysteinemia has been identified as a risk factor for coronary artery disease (CAD). South Asians appear to have a high incidence of CAD, while East Asians have a very low incidence. HYPOTHESIS: The present study was undertaken because the relative association of plasma homocysteine levels (PH) with CAD in South Asians (SA = Indian, Pakistani, Sri Lankan) and East Asians (EA = Chinese, Japanese) is not known. METHODS: Fasting PH were drawn on all patients with CAD of SA (age 62.4+/-1.1 years, 72 men, 14 women) and EA (age 61.8+/-3.0 years, 13 men, 4 women) descent. These were compared with PH available from Caucasian (CA) patients (age 61.1+/-1.1 years, 89 men, 17 women) with CAD. RESULTS: The PH in SA, EA, and CA patients were 11.0+/-0.5, 7.6+/-0.5, and 10.8+/-0.6 micromol/l, respectively (p<0.001 between EA and SA/CA). Percentages of SA, EA, and CA with elevated PH (> 12.0 micromol/l) were 33.7, 5.9, and 28.2%, respectively. There were no significant differences in the lipid subfractions between the SA and EA group. History of smoking was significantly higher in the EA (52.9 vs. 26.2%), while hypertension and diabetes mellitus had similar prevalences. CONCLUSION: Significant differences in PH of SA versus EA patients with CAD exist. The relative contribution of homocysteine in the development of CAD appears to be less in EA immigrants. In contrast, the association between CAD and PH in SA immigrants appears to be similar to that of Caucasians.

Analysis of Variance↗
PubMed1998

Ethics of resource allocation in developing countries: the case of Sri Lanka.

The issues of prioritization of health care services and allocation of resources have recently received increasing attention and discussion. Several reports have been published by governments in different countries and the issues are discussed in many recent books and papers. In this paper the focus is on the problems faced by a developing country when allocation of health care resources is considered. We consider these issues under three headings and exemplify the situation in a developing country by taking Sri Lanka as an example. Firstly the evidence to formulate an ethical basis for the existing health care system in Sri Lanka is discussed, in particular the problem of defining a minimum quality of health care for the population. Secondly, we consider the issues which arise when we want to formulate the ethical basis for health sector reform. In particular, we examine current World Bank proposals. We shall argue that there are a number of important conceptual and ethical issues that have not been properly addressed in the various policy documents. Finally, we introduce our own alternative ethical framework for policy reform.

Developing Countries↗
PubMed1995

Family studies in chromosome 22q11 deletion: further demonstration of phenotypic heterogeneity.

We describe three unrelated, Scottish infants with the velocardiofacial/DiGeorge syndrome, all of whom have deletions of chromosome 22q11. Two of the infants had inherited the deletion from their mothers; the third infant's mother had clinical features although a deletion was not demonstrable in her. One infant had craniosynostosis associated with broad thumbs which may be a separate familial trait; however, at least one other 22q11 deleted individual with craniosynostosis is known and it is possible that craniosynostosis is a rare feature of this deletion syndrome. The second infant is the third reported case with isolated hypoparathyroidism and dysmorphic features associated with the 22q11 deletion. The variable clinical phenotype of these families with 22q11 deletion is discussed and compared with other reported families.

Adult↗
PubMed1989

A double-blind comparative study: amineptine (Survector 100) versus imipramine.

The aim of the study was to compare the antidepressant effects of amineptine with imipramine in depressive illness. According to the DSM-III criteria, 33 patients diagnosed as having depressive illnesses were given either imipramine or amineptine, 50-100 mg and 100-200 mg, respectively, per day on a double-blind basis over a period of 2 months. Both groups presented steady improvement of the symptoms of depression during treatment, as scored on the Hamilton and Montgomery and Asberg Depression Rating Scales and Clinical Global Impression Scale. Amineptine produced fewer anticholinergic effects than imipramine. The results show that amineptine, as well as imipramine, is well suited for treating depressed patients.

Adult↗